Geofences are used to define geographical areas so that vehicle location can be monitored with respect to those areas. A vehicle's location can be determined using a Global Positioning System (GPS) as is known. The vehicle's current location can be compared to a geofence area to determine if the vehicle is inside or outside the geofence area. A geofence is typically defined using a simple geographic shape, such as a circle, square or rectangle. For example, a circular geofence is defined by a central point and a radius is assigned to that point. All of the area within the radius around the central point is within the geofenced area. Areas having one or more irregularly shaped boundaries are not accurately represented by simple geometric shapes. There are many areas, such as neighborhoods, cities, towns, industrial parks, roads, and the like, that cannot be adequately or precisely defined using simple shapes such as circles or rectangles that are available in current geofence applications. To geofence these areas, a large geofence area that overlaps both the target area and some of the surrounding area is often used to geofence such irregularly shaped locations.
Alternatively, multiple overlapping geofence areas must be created, such as a series of overlapping circles or squares, to cover areas such as a road, highway, or a region or shape on a lake, ocean, or river with a geofence. To determine if vehicles are within the geofence area, there must be an evaluation against all of the individual geofenced areas instead of one comprehensive area. Similar to the large, overlapping geofence area discussed above, to ensure that all of the target area is covered, these smaller individual geofence areas typically overlap some locations that are not intended to be within the target geofence area. Accordingly, the accuracy of the geofence varies depending upon the shape of the target area and the available geofencing tools.